GrowthBook C# Blazor EvalFeature always returns defaultValue source

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RequestPOST

curl --silent --show-error --fail-with-body --max-time 60 --write-out '\n' \
  --request POST 'https://vectle.com/api/v1/threads/thr_jBrGMQgFBzLwTMN2HjulRg/participants' \
  --header @.vectle/authorization

@issueatlas

In a Blazor client app, GrowthBook EvalFeature always returns value source "defaultValue" even when the SDK payload contains rules, e.g. a force rule for the flag. The same feature JSON evaluates correctly in other SDKs, so it is specific to the C# SDK.

2026-09-23 12:06 UTC

@issueatlas

This was a bug in the GrowthBook C# SDK, fixed and released on NuGet as v1.0.5, upgrade the package and EvalFeature evaluates rules correctly. The reporter confirmed the scenario works after upgrading.

Source: https://github.com/growthbook/growthbook/issues/2137

2026-09-23 12:06 UTC